Pressure fluid motor



May 3l, 1932. E. G. GARTIN PRESSURE FLUID Moron -Filed sept. (so,v 1929 Patented May 31, I193? UNITE y raamt` rT'ENr carlos LMER G. GARTIN, F CLAB'EMONT, NEW HAMPSHIRE, ASSIGNORTO SULLIVAN MACHINERY COMPANY, A. CORPORATION OF MASSACHUSETTS ERESSURE FLUID MOTOR Application lled September 30, 1929. Serial No. 396,337.

This invention relates to pressure fluid motors and more particularly to improved pressure fluid motors of the impact type.

An object of this invention is to provide an improved pressure fluid motor. Another object is to provide an improved pressure fluid motor of the valveless type. A further object is to provide an improved pressure fluid motor of the impact type having ini-p proved duid distribution means. Still anotherl object is to rovide an improved valveless motor of the iammer piston type whereby with the improvements incorporated therein it is made possible to form the motor cylinder with a substantially uniform bore and the hammer piston with a substantially smooth exterior surface, thereby eliminating all differential cylinder bores, dierential piston heads or spools and external circumferential grooves on the piston. A still further object is to provide an improved valvelesstype hammer motor in which eXtreme simplicity and ruggedness of design are attained without sacrifice of efficiency or power.

These and other `objects and advantages of this invention will, however, hereinafter more fully appear.

In the accompanying drawings there is shown for purposes of illustration one form which the invention may assume in practice.

In the drawings,-

Fig. 41 is a central longitudinal sectional view illustrating a percussive tool having the illustrative embodiment of the improved pressure fluid motor incorporated therein.

Fig. 2 is a view similar to Fig. 1 showing' the hammer piston in a different position.

Fig. 3 is a transverse sectional view taken l substantially on line 3 -3 of Fig. 1.

In this illustrative construction there is shown a percussive tool of the pressure duid 'operated type including a motor cylinderl having a bore 2 in which there is mounted for reciprocatory movement a hammer piston.3. This hammer piston 1s of uniform diameter fitting the bore 2 and has formed thereon a forwardly projecting striking bar 4 which, when the hammer piston nears the forward end of its forward stroke, entersV a reduced bore 5 formed within the integral thereto by the striking bar of the hammer piston. The implement 8 has formed thereon ausualcollar 9 arranged within a cham-v ber 10 formed within a retaining member having a central opening 12 through which the shank of the implement 8 extends. Interposed between the retaining member 11 and a split retaining washer 13 is an annular shock absorbing member 14'. The elements 11, 13 and 14 of the chuck are supported within a chuck housing 15 secured as by a transverse bolt 16 to the forward end of the motor cylinder. The rear end of the cylinder bore of the motor is closed by a detachable back head member 17 which is held in position by a handle member 18 suitably secured to the motor cylinder. Formed within this handle member is a fluid sup ly passage 19 through which pressure fluid is conducted under the control of a throttle valve 20 to supply passages 21 which communicate with an annular groove 22 herein preferably formed in the cylinder wall midwa between the ends of the cylinder bore 2. s shown, one side of the hammer piston 3 is'ilattened at 23 throughout a substantial portion of its length, 'and formed centrally within the hammer piston is a chamber 24. Herein formed integral with the head member 17 is a hollow sleeve-like extension projecting forward within the piston chamber 24, the forward end of this extension being closed by a transverse wall 26. The diametrically opposite sidestof the extension 25 are flat-- tened at 27 and the walls of this extension or grooves. A passage 32 connects the bore I 5 directly te atmosphere.

. bore 5 and passage 32.

The operation of the improved pressure fluid motor will now be described. vWhen the parts are inthe position shown in Fig. l with thethrottle valve 2() opened7 pressure fluid flows through the supply connection 19 past the throttle valve 2O and through passages 21 to the annular groove22 formed centrally in the wall of the motor cylinder. At this time the front end of the cylinder bore is connected directly to exhaust through The pressure fluid flows from the central groove 22 past the fiattened portion 23 on the piston 3 to the enlarged rear grooved or enlarged portion Si of the cylinder bore. The pressure duid acts on the annular pressure area at the extreme rear end ot the piston, causing the latter to move forward. at .the same time admitting pressure fluid through the flattened portions T on the extension 25 to the piston chamber 24. The pressure acting on the pressure area atthe forward end of the piston chamber 24 supplements the pressure acting on the annular rear end surface of the piston, thereby driving the piston forward within the cylin-l der here to deliver a powerful blow on the shank of the implement 8. As the piston moves Jforward the flattened portion 23 on the piston moves out of communication with the internally enlarged rear end portion 31 of the cylinder bore` thereby cut-ting oli the flow or" pressure fluid to' the.rear end of the cylinder bore. rllhe pressure fluid at. the rear end of the cylinder here then acts expansively. driving the piston forward. As the hammer piston 3 moves further forward the ports Q8 formed in the extension 25 are opened. thereby connecting the cylinder bore at the rear end of the hammer piston directly to atmosphere through the passage 29. As the piston continues its forward movement the flattened portion 23 on the piston moves into communication with the internally enlarged front end 30 of the cylinder bore, connecting the front end of the cylinder bore with the fluid supply groove 22. As the hammer piston nears the forward end of its working stroke the'strilring bar 4 enters the bore 5. thereby closing the passage 32 and cutting ofi communication of the Yiront end of the cylinder bore with the exhaust. Upon continued forward movement of the hammer 'piston the striking bar 4 delivers its hlow on the shank ofthe implement 8. When the parts are in the position shown in Fig. 2

pressure fluid Hows through passages 21, an-

nular groove 22. flattened portion 23 on the piston and groove 30 to the. forward end ot' the cylinder bore to act on the front pressure area on the hammer piston, driving the latter rearward. As the hammer piston moves rearward the flattened portion 23 on the piston is .moved out of communication with the front end of the cylinder bore and the pressure within the front end of the cylinder bore then acts expansively, driving the piston rearward. Upon continued rearward movement of the piston the ports 28 are first closed, cutting ofi the exhaust for the rear end of the cylinder bore and upon further movement of the piston the striking bar 4 moves out of the here 5, opening the front end of the cylinder bore directly to exhaust through passage 32. At substantially the same time the rear end of the cylinder bore is brought into communication with the'supply groove 22 by the flattened portion 23 on the piston, the piston moving rearward by momentum to complete its return stroke. The cycle of operation described above is then repeated,

thereby causing the hammer piston to reciprocate rapidly within the motor cylinder, tl'iercby causing a hammering action to be' imparted to the shank et the implement 8.

As a result ot this invention an improved pressure fluid motor is provided which is eX- tremely powerful and efficient and at the. same time is simple and rugged in design. lt will turther he noted that an'improved valveless pressure fluid motor is provided wherein by the improvements disclosed. herein it is possible to form the cylinder bore et a substantially uniform diameter\and the hammer piston with a substantially smooth exterior surface, thereby eliminating all differential cylinder bores, piston heads or spools3 and circumferentially extending grooves on the piston. It will still further be evident that by providing a valveless motor having the improved motor exhaust arrangement and a cylinder with a substantially uniform bore and a hammer piston of substantially uniform diameter, the cost of manufacture has been materially reduced and a more rugged and etiicient. motor produced.

While there is in this application' specifically described one form which this invention may assume in practice, it will be understood that this 'lform of the same is shown for purposes of illustration and that the invention may he modified-./,and embodied in various other forms without departing from its spirit or the scope ofthe appended claims.

Vihat I claim as new and desire to secure by Letters Patent is: I..

l. In a pressure fluid motor, a cylinder, a piston reciprocable therein and having a bore closed save at its rearward end, piston controlled means for admitting fluid to said cylinder to effect opposite movementsot` the piston in alternation, and means for exhausting fluid from the cylinder including a tube having a portion providing a lateral surface conforming in shape to and having a working fit with the wall of the bore in the pistonand provided with a port opening through Jaid portion within the borders of said surace.

2. In a pressure fluid motor, a cylinder, a piston reciprocable therein and having a bore closed save at its rear end, piston controlled ton including means for 'intermittently supplyingiuidv under pressure to act upon the end of the piston through which said bore opens, means telescoping within said bore controlling exhaust of the fluid so admitted, and means for connecting the innermost end of the bore constantly in communication with the space within the cylinder bore adjacent saidend of the piston.

4. In a pressurerluid motor, a cylinder, a piston reciprocable therein and having a longitudinal bore closed save at one end and means for effecting reciprocation of said pis- 4ton including piston controlled means for intermittently supplying iuid under pressure to act upon the end of the piston through which said bore opens, means telescoping within said bore controlling exhaust of the Huid so admitted, and means for connecting the innermost end of the bore constantly incommunication with the space within the cylinder bore adjacent said end of the piston.

5. In a pressure fluid motor, a cylinder, a piston therein having a bore closed at one end. said cylinder having an inwardly pro jecting member telescoping with said bore, means for imparting opposite movements to said piston including means for admitting pressure intermittently to act on the inner end of said bore and on the end of the piston surrounding the mouth of the bore, and exhaust means controlled by piston movement and including a passage formed in said projecting member.

In testimony whereof I ailx my signature.

ELMER G. GARTIN.

one end and means for effecting reciprocation of said pls- 

